关键词: 奥氏体不锈钢, 加工硬化, 显微硬度, 屈服强度, 微观结构

Abstract:

Rational experiments based on Taguchi methods were designed according to the characteristics of difficult-to-machine material 0Cr18Ni9 stainless steel.Work hardening was discussed from the micro-hardness and microstructure.Micro-hardness distribution of the machined sub-surfaces was
got with the Vickers hardness measurement.And an empirical formula was established
for predicting the yield strength with hardness.
Microstructure of the hardened layer was observed with scanning electron microscopy.
The results show serious hardening that the degree of work hardening is more than
150%,and the depth of machining affected zone is more than 100μm.The yield strength
 follows a similar trend as that of the measured value of micro-hardness.Metallographic
observation shows that sub-hardened layer consists of the thermal-force influenced layer
and the force influenced layer,while the thermal-force influenced layer contains defects,
and it is easy to peel off. These results indicate that great changes have happened in the surface and subsurface after turning, and it is important to use reasonable cutting parameters to reduce cutting forces and cutting temperature and then reduce work hardening.

Key words: Austenite stainless steel, work hardening, micro-hardness, yield strength, microstructure